This invention relates to a method of insulating with an inorganic, non-combustible foam and, more particularly, to a foam which constitutes an improvement on Canadian Patent No. 830,526 and corresponding U.S. Pat. No. 3,466,221.
In the above-mentioned patents, an expanded silicate insulation was developed utilizing 80 to 90% of sodium silicate, 3 to 6% asbestos fiber, 0.2 to 0.6% silicon metal and 6 to 15% sodium silico fluoride to provide a mass three times its original thickness.
I have found that by substantially increasing the silicon metal using a specific filler other than asbestos fiber and in a higher amount, and a much lower sodium silicate, I can obtain substantially higher foam volume.
In particular, I employ about 64% of sodium silicate in one package constituting a liquid ingredient and in another package about 8% silicon metal, about 20% of a a filler selected from the class consisting of wollastinite, perlite and mixtures thereof and about 8% sodium silico fluoride. These, when mixed, generate foam at least of the order of 6 times the volume of the packaged contents.
As such, the resultant product is exceptionally suitable for use in cavities, wiring and for insulation purposes, etc. This eliminates the messy water and cement spray that are presently used. The fire retardant spray-on insulation for industrial, commercial and residential construction may be used for wood or steel column temperature rise criteria, or as a spray-on insulation for steel walls, roof or concrete construction.
The product under room temperature will foam in approximately 2 hours and if some heat is applied will foam in approximately 10 minutes.